The present invention relates to caulking guns and, more particularly, to mechanically operated caulking guns of the type employing dual component cartridges and dual actuating ejector rams for dispensing dual component materials.
There are different types of mechanically operated caulking guns. One of the more familiar ones in the type that uses a ratchet operated by a handgrip to advance a ram rod for dispensing of the caulking material. A second type of mechanical caulking gun is that which utilizes a thread and screw type of mechanism to advance a ram rod for ejecting of the material. It is this latter type to which the present invention is directed.
The caulking industry in recent years has been utilizing dual component materials. These dual component materials are of an epoxy type in many cases and are intermixed in a static mixer and through chemical reaction set up after dispensing. Some of these materials are of different viscosities which create uneven ejection pressures on the ejection rams. Additionally, some of the materials are very thick and difficult to eject and require considerable ejection ram pressure.
The mechanical screw-nut type dual component dispensing guns available in the prior art are subject to jamming by reason of the uneven dispensing pressures created on the ejection pressure creating mechanism. Additionally, such prior art devices utilize a conventional screw and nut type of ejection mechanism and the required pressures very often make operation or rotation of the conventional screw assembly extremely difficult for the operator. Further, the prior art devices suffer from a problem of reverse threading of the screw member by the pressure build up in the cartridges once the operator removes the torque from the screw.
The foregoing problems of conventional prior art caulking guns are addressed in the caulking gun of the present invention.